[coroutines] Switch to using std::experimental namespace per P0057R5

Summary:
Look for coroutine_traits and friends in std::experimental namespace.
Patch (mostly) by EricWF.

Reviewers: cfe-commits, EricWF, rsmith

Subscribers: majnemer, mehdi_amini

Differential Revision: https://reviews.llvm.org/D25068

llvm-svn: 283170

1 files changed, 5 insertions, 4 deletions

diff --git a/clang/lib/Sema/SemaCoroutine.cpp b/clang/lib/Sema/SemaCoroutine.cpp
index 461ca8eddcf..f9c3970e021 100644
--- a/clang/lib/Sema/SemaCoroutine.cpp
+++ b/clang/lib/Sema/SemaCoroutine.cpp
@@ -26,15 +26,15 @@ using namespace sema;
 static QualType lookupPromiseType(Sema &S, const FunctionProtoType *FnType,
                                   SourceLocation Loc) {
   // FIXME: Cache std::coroutine_traits once we've found it.
-  NamespaceDecl *Std = S.getStdNamespace();
-  if (!Std) {
+  NamespaceDecl *StdExp = S.lookupStdExperimentalNamespace();
+  if (!StdExp) {
     S.Diag(Loc, diag::err_implied_std_coroutine_traits_not_found);
     return QualType();
   }
 
   LookupResult Result(S, &S.PP.getIdentifierTable().get("coroutine_traits"),
                       Loc, Sema::LookupOrdinaryName);
-  if (!S.LookupQualifiedName(Result, Std)) {
+  if (!S.LookupQualifiedName(Result, StdExp)) {
     S.Diag(Loc, diag::err_implied_std_coroutine_traits_not_found);
     return QualType();
   }
@@ -86,7 +86,7 @@ static QualType lookupPromiseType(Sema &S, const FunctionProtoType *FnType,
   QualType PromiseType = S.Context.getTypeDeclType(Promise);
   if (!PromiseType->getAsCXXRecordDecl()) {
     // Use the fully-qualified name of the type.
-    auto *NNS = NestedNameSpecifier::Create(S.Context, nullptr, Std);
+    auto *NNS = NestedNameSpecifier::Create(S.Context, nullptr, StdExp);
     NNS = NestedNameSpecifier::Create(S.Context, NNS, false,
                                       CoroTrait.getTypePtr());
     PromiseType = S.Context.getElaboratedType(ETK_None, NNS, PromiseType);
@@ -345,6 +345,7 @@ StmtResult Sema::ActOnCoreturnStmt(SourceLocation Loc, Expr *E) {
   }
   return BuildCoreturnStmt(Loc, E);
 }
+
 StmtResult Sema::BuildCoreturnStmt(SourceLocation Loc, Expr *E) {
   auto *Coroutine = checkCoroutineContext(*this, Loc, "co_return");
   if (!Coroutine)